* [PATCH] jfs: UBSAN: shift-out-of-bounds in dbFindBits
@ 2024-07-10 0:12 Remington Brasga
2024-08-23 18:16 ` Dave Kleikamp
0 siblings, 1 reply; 2+ messages in thread
From: Remington Brasga @ 2024-07-10 0:12 UTC (permalink / raw)
To: Dave Kleikamp, Manas Ghandat, Juntong Deng, Andrew Kanner,
Osama Muhammad, Shuah Khan
Cc: jfs-discussion, linux-kernel, linux-kernel-mentees,
syzbot+e38d703eeb410b17b473, Remington Brasga
Fix issue with UBSAN throwing shift-out-of-bounds warning.
Reported-by: syzbot+e38d703eeb410b17b473@syzkaller.appspotmail.com
Signed-off-by: Remington Brasga <rbrasga@uci.edu>
---
When nb = 32, `mask = mask >> nb` or shorthand `mask >>= nb` throws
shift-out-of-bounds warning.
`mask = (mask >> nb)` removes that warning.
Link to the syzbot bug report: https://lore.kernel.org/all/0000000000006fc563061cbc7f9c@google.com/T/
fs/jfs/jfs_dmap.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
index cb3cda1390ad..636aae946e84 100644
--- a/fs/jfs/jfs_dmap.c
+++ b/fs/jfs/jfs_dmap.c
@@ -3020,7 +3020,7 @@ static int dbFindBits(u32 word, int l2nb)
/* scan the word for nb free bits at nb alignments.
*/
- for (bitno = 0; mask != 0; bitno += nb, mask >>= nb) {
+ for (bitno = 0; mask != 0; bitno += nb, mask = (mask >> nb)) {
if ((mask & word) == mask)
break;
}
--
2.34.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] jfs: UBSAN: shift-out-of-bounds in dbFindBits
2024-07-10 0:12 [PATCH] jfs: UBSAN: shift-out-of-bounds in dbFindBits Remington Brasga
@ 2024-08-23 18:16 ` Dave Kleikamp
0 siblings, 0 replies; 2+ messages in thread
From: Dave Kleikamp @ 2024-08-23 18:16 UTC (permalink / raw)
To: Remington Brasga, Manas Ghandat, Juntong Deng, Andrew Kanner,
Osama Muhammad, Shuah Khan
Cc: jfs-discussion, linux-kernel, linux-kernel-mentees,
syzbot+e38d703eeb410b17b473
On 7/9/24 7:12PM, Remington Brasga wrote:
> Fix issue with UBSAN throwing shift-out-of-bounds warning.
>
> Reported-by: syzbot+e38d703eeb410b17b473@syzkaller.appspotmail.com
> Signed-off-by: Remington Brasga <rbrasga@uci.edu>
> ---
> When nb = 32, `mask = mask >> nb` or shorthand `mask >>= nb` throws
> shift-out-of-bounds warning.
> `mask = (mask >> nb)` removes that warning.
Looks good. Applied.
Shaggy
>
> Link to the syzbot bug report: https://lore.kernel.org/all/0000000000006fc563061cbc7f9c@google.com/T/
>
> fs/jfs/jfs_dmap.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c
> index cb3cda1390ad..636aae946e84 100644
> --- a/fs/jfs/jfs_dmap.c
> +++ b/fs/jfs/jfs_dmap.c
> @@ -3020,7 +3020,7 @@ static int dbFindBits(u32 word, int l2nb)
>
> /* scan the word for nb free bits at nb alignments.
> */
> - for (bitno = 0; mask != 0; bitno += nb, mask >>= nb) {
> + for (bitno = 0; mask != 0; bitno += nb, mask = (mask >> nb)) {
> if ((mask & word) == mask)
> break;
> }
^ permalink raw reply [flat|nested] 2+ messages in thread
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